SCALA-32

scala-core/src/main/scala/com/baeldung/scala/FunctionsAndMethods.scala → scala-lang/src/main/scala/com/baeldung/scala/functionsandmethods/FunctionsAndMethods.scala

@@ -1,4 +1,6 @@
-package com.baeldung.scala
+package com.baeldung.scala.functionsandmethods
+
+import scala.annotation.tailrec
 
 object FunctionsAndMethods {
   // Anonymous function execution
@@ -23,6 +25,27 @@ object FunctionsAndMethods {
 
   // Here we defined a Value Class with extension method
   implicit class IntExtension(val value: Int) extends AnyVal { def isOdd: Boolean = value % 2 == 0 }
+
+
+  def plot(f: Double => Double): List[Double] = {
+    val xs: Range = -10 to 10
+    xs.map(x =>  f(x)).toList
+  }
+
+  val lines: (Double, Double, Double) => Double = (a,b,x) => a * x + b
+
+  val line: (Double, Double) => Double => Double = (a,b) => x => lines(a,b,x)
+
+  def factorial(num: Int): Int = {
+    @tailrec
+    def fact(num: Int, acc: Int): Int = {
+      if (num == 0) acc else fact(num - 1, acc * num)
+    }
+
+    fact(num, 1)
+  }
+
+  def pop[T](seq: Seq[T]): T = seq.head
 }
 
 

scala-core/src/test/scala/com/baeldung/scala/FunctionsAndMethodsUnitTest.scala → scala-lang/src/test/scala/com/baeldung/scala/functionsandmethods/FunctionsAndMethodsUnitTest.scala

@@ -1,4 +1,4 @@
-package com.baeldung.scala
+package com.baeldung.scala.functionsandmethods
 
 import org.junit.Assert.assertEquals
 import org.junit.{Before, Test}
@@ -43,4 +43,33 @@ class FunctionsAndMethodsUnitTest {
     assertEquals(true, 10.isOdd)
     assertEquals(false, 11.isOdd)
   }
+
+  @Test
+  def givenLine45_whenUseItInAPlot_thenCorrectResults(): Unit = {
+    val a45DegreeLine = FunctionsAndMethods.line(1,0)
+    val results = FunctionsAndMethods.plot(a45DegreeLine)
+    val expected = List(-10.0, -9.0, -8.0, -7.0, -6.0, -5.0, -4.0, -3.0, -2.0, -1.0,
+                        0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0)
+    assertEquals(expected, results)
+  }
+
+  @Test
+  def givenNestedMethod_whenUseIt_thenCorrectResults(): Unit = {
+    val factorialResult = FunctionsAndMethods.factorial(10)
+    val expected = 3628800;
+    assertEquals(expected, factorialResult)
+  }
+
+  @Test
+  def givenParameterizedMethod_whenUseIt_thenCorrectResults(): Unit = {
+    val strings = Seq("a", "b", "c")
+    val first = FunctionsAndMethods.pop(strings)
+    assertEquals("a", first)
+
+    val ints = Seq(10, 3, 11, 22, 10)
+    val second = FunctionsAndMethods.pop(ints)
+    assertEquals(10, second)
+
+
+  }
 }